Savannah Pierce's body was found Sept. 23 in a shallow grave in a wooded area of Williamson County, and deputies are investigating her death as a murder.

Pierce, a 30-year-old mother of three from outside Bristol, Tennessee, had moved to Maury County about a month before she disappeared to live with a former boyfriend she had reconnected with, according to her mother, Aleta Peters. Peters spoke to WSMV, which first reported the family's account.

The family last heard from Pierce on Sept. 7. When she did not answer calls on her birthday, Peters said she knew something was wrong. The family reported her missing to the Maury County Sheriff's Office on Sept. 22.

Peters said the family first contacted the boyfriend, who told them Pierce had left with another man on a motorcycle. The family did not believe his account.

A volunteer private investigator began tracking where Pierce was last seen and where the boyfriend had traveled. Peters told WSMV the investigator discovered Pierce's remains at one of those locations.

According to Peters, investigators told her Pierce had been wrapped in plastic and buried in a shallow grave in Williamson County. Rocks had been placed on top to conceal the burial.

The Williamson County Sheriff's Office (WCSO) confirmed to WSMV that the death is being investigated as a homicide. WCSO said investigators have identified persons of interest. No arrests have been made.

Deputies said there is no ongoing threat to the public.

Peters alleged that investigators described a violent sequence of events on Sept. 14, hours after the boyfriend took Pierce to a hospital for a hand injury. "They got into an argument and he beat her half to death and then shot her," Peters said, relaying what she said investigators told her.

Deputies in multiple counties are investigating how Pierce's body was moved from a home in Maury County to the wooded area of Williamson County. The Maury County Sheriff's Office led the initial search. WCSO joined after learning Pierce had reportedly lived in Williamson County, though the family's account places her living with the boyfriend in Maury County.

WCSO said it will not release additional details to protect the integrity of the investigation.

Anyone with information can contact the Williamson County Sheriff's Office or the Maury County Sheriff's Office.